Currently, the upgrading of heavy crude oils is carried out mainly by thermal cracking or hydrocracking based on the carbon rejection or hydrogen addition routes. These processes have several problems such as coke deposition on the reactor walls and on the catalyst, the obtention of low-quality products or a low efficiency in the use of hydrogen. An efficient technology for producing high quality distillates from heavy crude oils or residues has not been developed. An alternative to improve the yield of high-value liquid products in the hydroprocessing of crude oils is the use of polymers as heterogeneous hydrogen donors, developed for hydrogenation reactions as described in Patent Application MX/E/2014/079971, in which polymers containing naphthenic-aromatic polycyclic units, such as naphthalene units, can be reversibly hydrogenated-dehydrogenated in the reaction mixture. The addition of hydrogen in heavy oil upgrading is limited by the availability of hydrogen, which must be transferred to the liquid phase before starting the hydrogenation reaction. In conventional hydroprocessing, the hydrogen availability is increased by increasing the partial pressure of hydrogen; the use of conventional hydrogen donors provides an additional quantity of hydrogen for the hydrogenation reaction. Hydrogen donor molecules are dehydrogenated by transferring hydrogen atoms to the heavy hydrocarbons, thus improving the quality of cracking products and inhibiting the polymerization of heavy molecules via a free radicals mechanism, resulting in a reduction in the coke formation and an increase in the yield of light and middle distillates.

DecalinTetralinNaphthaleneM.p. −43° C.−35° C. 80° C.B.p.193° C.207° C.218° C.
These compounds have physical properties such that, after mixing with a crude oil, require a separation process for their recovery and recycle, elevating the costs of the overall process. Several technologies that have been described using these hydrogen donors, in which they are identified as hydrogen donor diluents, are presented below.
Patent GB767592 describes a process and system for converting crude oil into lighter products by thermal cracking of the oils in the presence of a hydrogen donor diluent, such as partially hydrogenated aromatic streams, in which the purpose of the hydrogen donor is to transfer hydrogen to the heavier fractions in order to prevent coke formation during thermal cracking or coking operations.
Patent GB784136 claims a thermal cracking process to generate lighter products using hydrogen donor diluents, which are hydrogenated hydrocarbons from a stream with a 260-593° C. boiling point range with substantial proportions of condensed-rings aromatic hydrocarbons.
U.S. Pat. No. 3,413,212 describes a process for improving the properties of hydrocarbon cuts boiling above 204° C. to obtain hydrocarbon fractions in the gasoline boiling range using a hydrogen donor with a boiling point in the 290-593° C. range, with the aid of a crystalline aluminosilicate catalyst. The hydrogen donor is preferentially formed by partial hydrogenation of polynuclear aromatics, following a hydrogen transfer mechanism in the presence of a catalytic material, being decahydronaphthalene and 1,2,3,4-tetrahydronaphthalene some of the preferred hydrogen donors.
Canadian Patent CA1122914 describes a process for improving the properties of heavy hydrocarbon oils, such as specific gravity, viscosity and boiling range, using a hydrogen donor material under hydrocracking conditions. In this process an effluent with a 82-177° C. boiling range is re-hydrogenated and recycled into the hydrocracking zone at 300-570° C. An 11.1° API bitumen is converted into a 19.3° API crude oil.
Canadian Patent 1144501 describes a process for upgrading a heavy oil by admixing with a hydrogen donor diluent and subjecting the mixture to catalytic cracking in order to obtain higher value hydrocarbons. Thus, a fraction of gasoil generated in the above-mentioned process is subjected to hydrotreatment to be recombined with heavy oil in a new process.
Canadian Patent 1152924 describes a process for converting a high boiling point crude oil containing metals and at least 5% asphaltenes into an upgraded crude oil, using a hydrogen donor solvent at a pressure of 40-200 bar, temperature of 400-450° C. and 0.8-1.5 h−1 LHSV.
U.S. Pat. No. 4,294,686 describes a process for upgrading a heavy crude oil by combining it with a hydrogen donor diluent obtained from the hydrogenation of a light cycle oil and subjecting this mixture to catalytic cracking at a pressure of 2.5-6 MPa, a temperature of 400-460° C. and LHSV of 0.8-7.0 and h−1 in order to obtain higher value hydrocarbons. Subsequently, a gas oil fraction is subjected to hydrotreatment for combining it with heavy oil in a new process.
U.S. Pat. No. 4,363,716 claims a hydrogen donor solvent based on tetralin and naphthalene for upgrading heavy hydrocarbons to lighter products at 250-800° C. with residence times from 15 seconds to 5 hours, with subsequent removal of the atmospheric distillation fraction between 175-300° C. and hydrogenation of this fraction with a metallic catalyst to regenerate the hydrogen donor material.
U.S. Pat. No. 4,389,303 claims a process for converting a high boiling crude oil into light products using a hydro-visbreaking donor solvent constituted by mixtures of naphthenic base distillates in the 200-500° C. boiling range, solvent that is reacted with the crude oil at a pressure of 40-200 bar, 400-450° C. and LHSV 0.5-2 h−1.
U.S. Pat. No. 3,413,212 describes a process for improving the properties of hydrocarbon cuts boiling above 204° C. to obtain hydrocarbon fractions in the gasoline boiling range using a hydrogen donor with a boiling point in the 290-593° C. range, with the aid of a crystalline aluminosilicate catalyst. The hydrogen donor is preferentially formed by partial hydrogenation of polynuclear aromatics, following a hydrogen transfer mechanism in the presence of a catalytic material, being decahydronaphthalene and 1,2,3,4-tetrahydronaphthalene some of the preferred hydrogen donors.
U.S. Pat. No. 4,389,303 mentions a crude oil hydro-visbreaking process at temperatures of 400-450° C. without a catalyst, in the presence of a hydrogen donor solvent derived from the same crude oil or a similar crude oil, and molecular hydrogen. The conversion of high boiling point crude oils (between 200 and 530° C.) having high contents of residue, metals and asphaltenes (5%) is achieved at pressures of 120-150 bar, LHSV of 0.8-1.5 kg/L·h and gas circulation between 400-2,000 m3/MT. Naphthalene concentration remains constant in the circulation system and in the visbreaker promoting the conversion of the residue in the crude oil into distillable components by a molecular rearrangement of hydrogen.
U.S. Pat. No. 4,363,716 discloses a cracking process at 250-475° C. with short residence times (10 min-5 h) for upgrading heavy oil fractions favoring the selectivity towards distillates and reducing the coke formation, by means of a hydrogen donor solvent (C10-C14) obtained from the feedstock, that is recycled to the reaction zone after hydroprocessing; tetralin, alkyltetralins, dihydronaphthalene and dihydroalkylnaphthalenes are mentioned as specific hydrogen donors. The hydroprocessing step consists of a hydrogenation in the presence of a solid base-metal catalyst (Ni—Mo, Co—Mo, Ni—W) or a hydrogenation followed by a hydroisomerization in the presence of a solid acid catalyst (Si—Al, Si—Mg, Si—Al—Zr, acidic crystalline zeolites, phosphoric acid on kieselguhr) to obtain a fraction containing at least 30% by weight of hydrogenated 2-ring aromatic compounds in the 175 to 300° C. boiling range.
U.S. Pat. No. 4,592,830 refers to a hydro-visbreaking process for heavy oil fractions boiling above 538° C. using a hydrogen donor solvent (tetralin) obtained from the same heavy oil fraction. When the heavy oil fraction is heated in the presence of hydrogen and the solvent under hydro-visbreaking conditions (380-480° C.), a decrease in the heavy oil fractions in the feedstock is achieved. The process uses molybdenum dithiophosphate or dithiocarbamate in a concentration of molybdenum metal up to 1000 ppm based on total feed plus solvent. The reaction time is up to 10 hours, preferably 3 hours, under a pressure of 500 to 3000 psig. Using the hydrogen donor solvent, a greater solids reduction is achieved than without the solvent.
U.S. Pat. No. 4,604,186 describes the reduction of coke formation in heavy oil fractions (boiling range 370-510° C.) by combining hydrogen donors with the feedstock to a visbreaker and a fluid or delayed coker in series. The control of the quantity of hydrogen donor fed to both units allows for the control of the quantity of coke produced. The heavy fraction from the visbreaker effluent is the feedstock to the coker, and the light aromatic fraction from the coker, after hydrogenation, is recycled as hydrogen donor to the visbreaker. The operating temperatures of the coker and visbreaker are 370-510° C. and 427-525° C., respectively. The hydrogenated oil fraction is mixed with the residue in a proportion of 0.2 to 2 weight percent.
U.S. Pat. No. 4,615,719 discloses a process for visbreaking heavy residues from petroleum at an Equivalent Reaction Time of about 800 seconds at 427° C., without free hydrogen and in the presence of a highly aromatic hydrogen donor in a proportion of about 0.1 to 50 weight percent to obtain products with lower viscosities, the amount of donor being 20 weight percent relative to the heavy oil residue. The hydrogen donor may come from the FCC process or from a product of an origin different to petroleum. The visbreaking unit operates at a severity of 500 to 800 Equivalent Reaction Time seconds, temperature of 350-485° C. and a residence time of 1 to 60 minutes. The amount of hydrogen donor solvent is 0.1 to 20 weight percent of the heavy oil.
U.S. Pat. No. 4,640,765 discloses a method for cracking heavy crude oils containing at least 1 wt. % of asphaltenes without high pressure drops in the cracking towers due to coking. The authors describe a series of steps among which are: a) dividing the inside of the cracking tower vertically into at least two portions, communicated in the upper part; b) introducing the heavy oil, the hydrogen donor solvent and hydrogen; c) circulating the fluid keeping a temperature of 380-470° C., a pressure of 30-150 kg/cm2 and a flow velocity of at least 1 cm/s in the cracking tower, with a residence time of 0.2 to 10 h. The hydrogen donor solvent is a hydride of an aromatic hydrocarbon containing at least 30% by weight of polycyclic aromatic hydrocarbons. A suitable catalyst is an oxide or sulfide of Group VII and VI metals on alumina, silica, Si—Al, Al—B, Si—Al—B, Si—Al—Mg Si—Al—Ti or a natural or synthetic zeolite, in a continuous flow process using a velocity of 5-100 cm/s and a preferred residence time of 30 minutes. The fluid is discharged from the top of the cracking tower and the solvent fraction is recycled.
Patent EU 0272038 describes a process for cracking a heavy oil fraction with an asphaltenes content >1 wt. % using a demetallizing and desulfurizing catalyst and a hydrogen donor solvent such as tetralin with an aromatics content greater than 30%. The circulation of a hydrogen-containing gas inhibits coke formation. The reaction product is hydrogenated in the presence of a solid catalyst, keeping a flow of hydrogen to avoid plugging. The oil and solvent flow at a velocity of 2 cm/s and LHSV is 1 h−1 maximum. Temperature and pressure in the cracking reactor are kept at 380-470° C. and 30-150 kg/cm2 and in the hydrogenation reactor at 330-440° C. and 30-150 kg/cm2.
U.S. Pat. No. 4,857,168 describes a process for hydrocracking heavy oil fractions using a hydrogen donor as solvent, hydrogen gas and a hydrogenating catalyst in a reactor system at a temperature of 380-470° C. and a pressure of 30-150 kg/cm2. The solvent inhibits the formation of carbonaceous materials and is discarded, but the concentration of tetralin is maintained at or above a fixed level. The process is applied to heavy oil fractions containing 10-30 wt. % of asphaltenes, with at least 50% of the feed boiling above 350° C. The catalyst has a demetallizing function, and both reactors (cracking and hydrogenation) are of the fixed-bed type.
U.S. Pat. No. 4,966,679 claims a method for hydrocracking of heavy oil fractions into lighter products using a catalyst, a hydrogen donor solvent (tetralin) and hydrogen gas in a cracking reactor. The hydrogenation of the reaction products in the presence of a solid catalyst and hydrogen gas converts the toluene insolubles into toluene-soluble compounds, thus avoiding plugging of the equipment. The catalysts are used in proportions of 50-70% by volume in the cracking reactor and 60-95% in the hydrogenating reactor. The linear velocity of the liquid is 3.5 cm/s in order to prevent high pressure drop. In one part of the reactor 20% by volume of the catalyst, the heavy oil and the solvent are circulated at a velocity of 2 cm/s. The hydrogen donor solvent is a hydride of polycyclic aromatic compounds (30% aromatics). A catalyst with a hydrodemetallizing function is used in the cracking reactor (380-470° C., 30-150 kg/cm2) and a catalyst with a hydrodesulfurizing function is used in the hydrogenation reactor (330-440° C., 30-150 kg/cm2).
U.S. Pat. No. 4,592,830 refers to a hydro-visbreaking process for heavy oil fractions boiling above 538° C. using a hydrogen donor solvent (tetralin) obtained from the same heavy oil fraction. When the heavy oil fraction is heated in the presence of hydrogen and the solvent under hydro-visbreaking conditions (380-480° C.), a decrease in the heavy oil fractions in the feedstock is achieved. The process uses molybdenum dithiophosphate or dithiocarbamate in a concentration of molybdenum metal up to 1000 ppm based on total feed plus solvent. The reaction time is up to 10 hours, preferably 3 hours, under a pressure of 500 to 3000 psig. Using the hydrogen donor solvent, a greater solids reduction is achieved than without the solvent.
U.S. Pat. No. 5,891,829 discloses a hydroconversion process applied to extra-heavy oil in the well for improving its properties (viscosity, API gravity and distillates yield). The process employs a hydrogen donor, methane and steam, which are injected into the oil well, wherein the minerals in the formation act as catalysts for the hydroconversion process. The concentration of hydrogen donor is 0.15-20 mol/kg of crude oil, methane ratio is about 0.4 mol/kg of crude oil and enough steam is used to raise the temperature in the oil well to 175° C. in order to start hydroconversion. The iron compounds are selected from FeO, Fe2O3, Fe3O4 Fe2(SO4)3 and their mixtures.
Patent WO 2005/121020 refers to a method to produce hydrogen at a temperature below 900-1000° C. that involves heating hydrogen-containing materials that are capable of being processed in a hydrogenation unit, in the presence of a hydrogen donor, a catalyst that promotes catalytic hydrogen transfer and a base, at temperatures of 150-450° C., providing enough time to hydrogenate and dehydrogenate the hydrogen-containing material (1 to 4 h), in order to produce hydrogen and carbon and to collect the hydrogen generated. Neither carbon nor sulfur or nitrogen oxides are emitted to the atmosphere, remaining in the reacting mixture in the form of salts (sodium sulfide, ammonium hydroxide). The hydrogen donor may be a hydride, C8-C22 hydrocarbons, crude oils, fuels, plastics, tires or asphalt in an amount of 20 wt. %, based on the reactor contents. The hydrogen donor pre-moistens the feed. The catalyst is introduced into the reactor in a proportion of 1-20% and the operating temperature is 150-450° C. The catalyst may be a saturated or unsaturated hydrocarbon, an alcohol, a fatty acid, catalytic forms of carbon, nickel, iron, palladium and their mixtures. As for the base, it is an alkaline metal compound (oxide, hydroxide, carbonate, bicarbonate), at a 10% proportion to the feedstock. The reaction is carried out in a reducing environment at an operating temperature of 250-300° C.; the ammonium salt is introduced with the feedstock.
Patent WO 2009/059369 describes a liquefaction process to produce liquid hydrocarbons from carbonaceous solids, promoting the reaction of the feedstock, a catalyst and a hydrogen donor with supercritical carbon dioxide at a temperature of 350-500° C. and a pressure of 500-3000 psi, where the catalyst is dispersed in a diluent which is a polar or aprotic solvent (water, methanol, ethanol, acetonitrile, dimethyl sulfoxide, dimethylformamide or mixtures of these), using a catalyst/feed ratio of 1-20, particle size of the solid carbonaceous material 200-300 mesh, solvent/carbonaceous material ratio of 1:1 to 5:1 and reaction time of 60 to 480 min.
U.S. Patent 2012/00612991 refers to a hydrothermal process for upgrading hydrocarbons by means of the introduction into a reactor of the heavy feedstock, water, a preheated hydrogen donor composition and steam at a temperature of 400-450° C. and a pressure of 24-26 MPa, in the absence of a catalyst, with a residence time of 1-30 minutes, enough to bring about modifications to the feedstock. The hydrogen donor is heated and kept at a temperature above 50° C. for 10 minutes. Feedstock/water ratio is 1:10 to 10:1 and hydrogen donor/feedstock ratio is 0.005:1 to 0.1:1. The hydrogen donor composition comprises tetralin, alkyltetralins, liquefied carbon extract, petroleum distillates or cracking products.
As described in the patent documents above, the use of liquid hydrogen donors such as tetralin or decalin to inhibit coke formation in crude oil upgrading is well known; however, these compounds are expensive and their recovery and reuse is difficult, which is why in this invention we propose the use of heterogeneous hydrogen donors (polymers prepared from monomers that contain a polycyclic aromatic, aromatic-naphthenic or naphthenic ring, such as naphthalene units, in their structure) in the hydrotreatment or hydrocracking of heavy hydrocarbons, such as heavy or extra-heavy crude oils and residues from the distillation of petroleum.

Naphthalene-Base Polymers With High Melting and Decomposition Temperatures
In heavy and extra-heavy crude oils thermal hydrotreatment processes it is feasible to use solid hydrogen donors in fixed bed, ebullated bed or slurry continuous operation or batch reactors to carry out hydroprocessing reactions. The present innovation refers to the application of these polymers as heterogeneous hydrogen donors in the hydrotreatment or hydrocracking of heavy hydrocarbons, such as heavy or extra-heavy crude oils and residues from the distillation of petroleum.
Some properties of the hydrogen donor polymers object of the present invention are:                Melting and decomposition temperatures above 450° C.        Chemical stability of the polymer structure (functional groups).        Possibility of improving textural properties.        Possibility of forming (extruding).        Preparation from commercial raw materials.        Preparation can be scaled up to industrial production.        
It is therefore an object of the present invention the application of polymers and co-polymers with naphthalene-, anthracene- or phenantrene-type units as heterogeneous hydrogen donors in the hydrotreatment or hydrocracking of heavy hydrocarbons, such as heavy or extra-heavy crude oils and residues from the distillation of petroleum; these heterogeneous hydrogen donors may be supported, anchored or in physical mixture with metallic oxides such as alumina, silica, titania or kaolin.
Another object of the present invention is the application of these heterogeneous hydrogen donor polymers, non-supported or supported on metallic oxides such as alumina, silica, titania or kaolin, as hydrogen donors in thermal hydrotreatment reactions of heavy or extra-heavy crude oils and cuts and streams derived from them, in the presence of hydrogen or methane-rich gas.
An additional object of the application of these heterogeneous hydrogen donor polymers is the improvement of some physicochemical properties of heavy or extra-heavy crude oils, such as viscosity, distillates yield and API gravity, while inhibiting the formation of coke in the hydrotreatment or hydrocracking of heavy hydrocarbons, such as heavy or extra-heavy crude oils and residues from the distillation of petroleum.
An additional object of the application of these heterogeneous hydrogen donors is in the hydrotreatment of petroleum fractions, such as naphthas, diesel, light and heavy gasoils, jet fuel, light cycle oil and bottom-of-the-barrel residues.
These and other objects of the present invention are set with more clarity and detail in the following chapters.